England must beat South Africa and hope that Samoa upset France on Saturday if they are to climb back into the top four of the world rankings this weekend.

The four leading sides in the International Rugby Board's official rating following the completion of the end of year internationals will be rewarded with a top seeding for the 2015 Rugby World Cup draw on December 3 and therefore will not be drawn alongside each other in the same pool.

New Zealand, South Africa, Australia and France currently occupy those positions with England, who will host the sport's showpiece event in less than three years' time, looking to force their way into the reckoning and avoid one of the sport's biggest sides in the early stages of the tournament.

Victories over Australia and Argentina have put France in control of their own destiny ahead of their last outing of the year against Samoa but the Islanders' victory over Six Nations champions Wales last weekend has the French on their guard.

A victory for France would see them keep England at bay but a defeat and a big win for Stuart Lancaster's side against South Africa would see them climb into the top four with their exact ranking dependent on Australia's return from their game against Italy.

Things begin to get a little complicated if France were to suffer a narrow defeat (by 15 points or less) and England were to beat the Boks by a similar margin with IRB officials then forced to go beyond the two decimal points they use for published ranking as the sides would be locked on 83.07 points. In such a scenario, England would edge ahead of their cross-Channel rivals.

Either way, depending on results, England may have one final opportunity to shake up the world order when they tackle New Zealand in their final clash of the year a week later.

A similarly fascinating battle is set to play out for the second group of seeds - those that are placed 5th-8th on the ranking. Those places are currently occupied by England, Argentina Ireland and Wales with Samoa threatening to become the first Tier 2 nation to break into the top eight in the world.

Victory over France would see Samoa make history while Ireland and Argentina will go head-to-head in a clash that will go a long way to deciding their World Cup fate. Wales, who will tackle New Zealand on Saturday, are in real danger of dropping out of the top eight and should that occur then they will face two of the sides above them in pool play at RWC'15. However, like England, they will have one final chance to boost their ranking when they tackle Australia at the start of next month.

A loss for Ireland, in tandem with other results, could see them plummet to 10th position and leave Declan Kidney's men facing a pool with two sides ranked higher than them. On the flip side, a loss for the Pumas and they could be the ones slipping out of the top eight.

Scotland are resigned to again being in band three for a Pool Allocation Draw as even a comprehensive win against Tonga this weekend will have little bearing on their current 10th spot. The Scots were drawn with two higher ranked sides for RWC 2011 and missed out on a quarter-final spot for the first time.

Italy may currently be ranked 11th but it is theoretically possible for them to squeeze into a top eight spot, providing they can record a first ever win over the Wallabies - and by more 15 points - and other results go their way.

If the Pool Allocation Draw was to happen today (19 November), the bands would be as follows:

All 12 automatically qualified teams are in action this weekend. Below is a table of exactly how this weekend's results could affect the automatically qualified teams' ratings points.

Ireland v Argentina, DublinCurrent rating: Ireland (IRE) 79.04; Argentina (ARG) 79.89
If home team wins by more than 15 points: IRE 80.22; ARG 78.71
If home team wins by 15 points or less: IRE 79.82; ARG 79.10
If away team wins by 15 points or less: IRE 77.82; ARG 81.10
If away team wins by more than 15 points: IRE 77.22; ARG 81.71
If it's a tie: IRE 78.82; ARG 80.10

England v South Africa, TwickenhamCurrent rating: England (ENG) 81.96; South Africa (RSA) 86.05
If home team wins by more than 15 points: ENG 83.62; RSA 84.39
If home team wins by 15 points or less: ENG 83.07; RSA 84.94
If away team wins by 15 points or less: ENG 81.07; RSA 86.94
If away team wins by more than 15 points: ENG 80.62; RSA 87.39
If it's a tie: ENG 82.07; RSA 85.94

Italy v Australia, FirenzeCurrent rating: Italy (ITA) 76.61; Australia (AUS) 85.94
If home team wins by more than 15 points: ITA 79.06; AUS 83.49
If home team wins by 15 points or less: ITA 78.24; AUS 84.31
If away team wins by 15 points or less: ITA 76.24; AUS 86.31
If away team wins by more than 15 points: ITA 76.06; AUA 86.49
If it's a tie: ITA 77.24; AUS 85.31

Scotland v Tonga, AberdeenCurrent rating: Scotland (SCO) 77.42; Tonga (TGA) 74.51
If home team wins by more than15 points: SCO 78.04; TGA 73.90
If home team wins by 15 points or less: SCO 77.83; TGA 74.10
If away team wins by 15 points or less: SCO 75.83; TGA 76.10
If away team wins by more than 15 points: SCO 75.04; TGA 76.90
If it's a tie: Sco 76.83; Tga 75.10

Wales v New Zealand, CardiffCurrent rating: Wales (WAL) 78.95; New Zealand (NZL) 92.91
If home team wins by more than 15 points: WAL 81.95; NZL 89.91
If home team wins by 15 points or less: WAL 80.95; NZL 90.91
If away team wins by 15 points or less: WAL 78.95; NZL 92.91
If away team wins by more than 15 points: WALl 78.95; NZL 92.91
If it's a tie: WAL 79.95; NZL 91.91

France v Samoa, ParisCurrent rating: France (FRA) 84.99; Samoa (SAM) 78.79
If home team wins by more than 15 points: FRA 85.11; SAM 78.67
If home team wins by 15 points or less: FRA 85.07; SAM 78.71
If away team wins by 15 points or less: FRA 83.07; SAM 80.71
If away team wins by more than 15 points: FRA 82.11; SAM 81.67
If it's a tie: FRA 84.07; SAM 79.71